JPS62266563A - Photoconductive toner - Google Patents

Abstract

PURPOSE:To efficiently transfer the carriers generated by light at the shortest distance and to improve photosensitivity by constituting a toner of a nuclide core material contg. an electric charge transfer material and a coating layer contg. an electric charge generating material provided on the surface of the nuclide core material. CONSTITUTION:This photoconductive toner is constituted of the electric nuclide core material 1 contg. the charge transfer material (CT material) and the coating layer 2 contg. the electric charge generating material (CG material). The carriers generated with the CG material in the coating layer by the light 3 irradiated to the coating layer 2 of a toner 6 can pass the core material 1 and can pass the shortest distance up to a substrate 4. The CT material is exemplified by an oxazole deriv., oxadiazole deriv., etc. The amt. of the CT material to be added is specified to about 0.1-90wt% by the weight of the resin. Any of inorg. and org. materials which generate the free carriers by absorbing visible light may be used as the CG material to be used for the coating layer. The amt. of the CG material is preferably 30-60wt% by the total weight of the coating layer.

Description

DETAILED DESCRIPTION OF THE INVENTION INDUSTRIAL ADVANTAGES The present invention relates to toners, particularly photoconductive toners, for use in electrophotography.

Conventional techniques/techniques Shizuka 71 in the electrophotographic process! The general method for forming a latent image is to form it on a photoreceptor consisting of a photoelectric charge generation layer, but in recent years, a method has been developed in which a photoreceptor is formed using a conventional photoreceptor and a photoconductor is added to the developer. A summer photo process using conductive toner has been proposed.

The method is to apply the latent image forming function to the toner white body.
It is a method that simplifies the electrophotographic process and does not require a sensor, which has the advantage of lowering manufacturing costs. Research and development is being actively conducted as a method that can form full-color images in one shot. (For example, JP-A No. 60-175056, JP-A No. 1987-13
3459, JP-A-60-258558, etc.)
.

” - Is the development of photoconductive toner the key to realizing the above-mentioned 7-boko photographic process?・Due to the difficulty of having to perform both functions as a developer and photoconductivity, it has not yet been put into practical use, especially as its photosensitivity is far from a practical level. Not yet.

JP-A-60-175056 discloses that spherical polymer core particles are mixed with a photoconductive substance and a minute polymer particle system, and the glass transition temperature (F) of the minute polymer particles is adjusted.
The present invention discloses a photoconductive toner produced by spray drying at a temperature above Tg) and a method for producing the same.

Figure 3 shows a conceptual diagram of the movement of the toner (, η) generated when the toner of the invention is irradiated with light. Since the core-core dispersion system (1) consists essentially only of an insulating polymer, the coating layer (2) provided as a charge generation layer is formed by the light (3) irradiated onto the toner. The carrier generated inside the toner has only a path (5) on the outermost surface of the toner, and since the coating layer does not contain a charge transport substance, it is difficult for the carrier to move, resulting in very poor photosensitivity.

Furthermore, if the toner is stacked in many layers, the contact resistance between the toner and the toner particles or between the toner and the substrate becomes very large, and no improvement in photosensitivity can be expected.

JP-A-60-133459 discloses a method for producing a leading conductive toner prepared by spray-drying a leading conductive substance and a thermoplastic resin dispersed in an aqueous solution. It does not contain a transport substance and is completely different from the laminated type toner disclosed in the present application.

Japanese Patent Application Laid-Open No. 258558 discloses a photoconductive toner characterized in that fine particles mainly containing a charge-generating substance and fine particles mainly containing a charge-transporting substance are mixed and then sphericalized by heat treatment. However, since the toner disclosed is not a laminated type toner, its structure is completely different from the toner disclosed in the present application.

Problems to be Solved by the Invention Since photoconductive toners have particularly poor photosensitivity and lack practicality, improvements are desired.

In view of these circumstances, the present invention aims to provide a photoconductive toner with excellent photosensitivity and stability.

Means for solving the problems, that is, the present invention is a method comprising (a) a nuclear core material containing a charge transporting substance and (b) a coating layer containing a charge generating substance provided on the surface of the nuclear core material. Concerning conductive toner.

A schematic diagram of the structure of the photoconductive toner of the present invention is shown in FIG.

In the figure, (1) shows a core substance containing a charge transport substance (CT substance), and (2) shows a coating layer containing a charge generating substance (CG substance). Fig. 2 shows a conceptual diagram of the movement of carriers generated by irradiation with . 1) has very good photoconductivity because it contains a CT substance.Therefore,
Light (3) irradiated onto coating layer (2) of toner (6)
.) allows the carrier generated from the CG substance in the coating layer to pass through the nuclear core substance (+) and travel the shortest distance to the substrate (4).

In addition, by including it in the CG animal substance coating layer, which is a light color, the thickness of the CG animal substance can be made thinner in the toner, and the translucency of the toner itself is improved. As a result, it is very advantageous for the photosensitivity when irradiating a single layer of a multilayer photoconductive toner.

As mentioned above, the features of the present invention are that the photogenerated carriers can travel the shortest distance to the substrate and have excellent light transmittance, which is very advantageous in improving photosensitivity. The resin used for the antibody core material is preferably a thermoplastic resin. Thermoplastic resins include polystyrene resin, acrylic resin, methacrylic resin, polyester resin, polyamide resin, polyethylene, polypropylene,
Polyvinylidene fluoride, polyvinylidene chloride, polyvinyl chloride, ethylene-vinylidene acetate copolymer, styrene-acrylic ester copolymer, styrene-methacrylic ester copolymer, styrene-butadiene copolymer, styrene-hynylidene chloride copolymer, styrene-vinyl chloride copolymer, styrene-vinylidene fluoride copolymer, styrene-acrylonitrile copolymer, Evokinju 11&,
Modified rosin, polyethylene wax, polycarbonate resin, etc. may be used alone or in combination.

C'F substances include oxazole derivatives, oxadiazole derivatives, deazole derivatives, deadiazole derivatives, triazole derivatives, imidazole derivatives, imidazole derivatives, imidazolinone derivatives, bisimidazolidine derivatives, pyrazoline derivatives, oxazolone derivatives,
Henzothiazole derivatives, benzimidazole derivatives,
Quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, 2°4.7-dolinitrofluorenone, 2,4, Examples include 5,7-titranitrofluorenone, 2,7-sinitrofluorenone, and the like. These CT substances can be used alone or in combination.

Since the nuclear core material mainly consists of the nuclear core material described above and CT material, the wavelength of the light source used for electrophotography is 450-7.
It has extremely high transmittance and good photosensitivity for 50 nm light.

The amount of C'F substance to be added is preferably such that it does not precipitate when nuclear particles are prepared together with the thermoplastic resin, and it also depends on the type of resin and C'F substance, or whether to add one or more types. It varies depending on the amount of resin, but 0.
About 1 to 95 wt%, preferably 30 to 80 wt%, more preferably 40 to 60 wt%. 0, Iw
If it is less than L%, the carrier transport ability in the core material will be poor, and if it is more than 95wt%, C'
Substance F precipitates, making granulation difficult.

Since the core material of the photoconductive toner of the present invention mainly consists of the thermoplastic resin and CT material, the photogenerated carrier is
It can be moved over the shortest distance and has good photosensitivity.

The particle size of the nuclear material is closely related to the final photoconductive particle size, and therefore affects the final image quality, especially the resolution, and is usually 1 to 30 μm, preferably 1 to 30 μm. 5-20
This is from μm. If it is smaller than 1 .mu.m, the fluidity and development characteristics of the toner will be poor, and if it is larger than 30 .mu.m, the final image quality, especially the resolution, will be poor. Note that although it is desirable that the core material is spherical, the shape is not limited because it becomes spherical by providing the coach ink layer.

As the CG substance used in the coating layer, either an inorganic substance or an organic substance may be used as long as it absorbs visible light and generates free carriers. For example, inorganic substances such as amorphous selenium, trigonal selenium, selenium-arsenic alloy, selenium-tellurium alloy, cadmium sulfide, cadmium selenide, mercury sulfide, lead oxide, and lead sulfide, as well as monoazo, nosazo, and trisazo dyes. Azo dyes, perylene dyes, anthraquinone dyes, polycyclic quinone dyes,
Innovoid dyes, phthalonanine dyes, carbonium dyes, gynonimine dyes, methine dyes, quinoline dyes, nitroso dyes, nitrone dyes, benzoquinone and naphthoquinone dyes, naphthalimide dyes, perinone dyes, or quinacridone dyes ¥'i'l seems to be indicated by etc.! It is better to use substances.

Furthermore, when a binder resin is used in the coating layer containing the CG substance, the resin described above as the core substance can be used as the resin.

In that case, the same resin as that used for the core particles may be used, or different resins may be used alone or in combination.

Furthermore, the coating layer containing the CG substance may contain a C'F substance to increase photosensitivity). In this case,
As the C'F substance, the same C'r substance as the C'r substance contained in the nuclear core particles may be used, or a different C'v substance may be used. Of course, you can add them alone or use them in combination.

The amount of the CG material contained in the coating layer is 5 to 100 wt%, preferably 20 to 80 wt%, more preferably 30 to 60 wt%, based on the entire area of the coating layer. If it is less than 5 wt%, the photosensitivity will generally be poor, and the print density as a final image may be insufficient.

When the CT substance is contained in the coating layer, the amount of the C'F substance contained is 0 to 80 wt%, preferably 0.1 to 50 wt%, more preferably 0.1 to 50 wt%, based on the entire coach ink layer. is 1 to 30 wt%.80 wt%; if it is too large, C'F substances may precipitate, making it difficult to form a coating layer.

The coach ink layer contains a C'r substance, which not only facilitates the movement of light through the rf layer, but also facilitates the movement of the core substance. The movement of carriers between the coating layer and the coating layer also becomes easy, and an improvement in photosensitivity is achieved.

A toner showing another embodiment of the present invention includes a C′r substance and a CG substance in the core substance, and a C′r substance and a CG substance in the coating layer.
Examples include a photoconductive toner containing a G substance or a photoconductive toner containing both a CG substance and a CT substance in both the core substance and the coating layer. Although the present invention does not include a CG substance in the nuclear core material, it is possible to add it in an amount that does not impair the effects of the present invention. However, as the number of these enemies increases, the light transmittance of the toner itself deteriorates, so that the effects of the present invention cannot be sufficiently obtained.

Note that a toner having a configuration opposite to that of the present invention, for example, a toner containing a CG material in the core material and a CT material in the coating layer, a toner containing a CG material in the core material, a CG material and a CT material in the coating layer, or A toner containing a CT material and a CG material in the core material and a c'r material in the coating layer cannot have sufficient light transmittance or good photosensitivity.

In the photoconductive toner of the present invention, known additives may be appropriately used in the core material or the coating layer. As such an additive, a conductive substance such as wax or fine powder of metal oxide may be added to the core material to improve the stability and conductivity. A charge control agent or a fluidizing agent can be added to the coating layer to improve charging properties and fluidity.

The core substance can be produced by emulsion polymerization or suspension polymerization of a mixture of the above-mentioned thermoplastic binder resin monomer or prepolymer, CT substance, and other additives. After dissolving it in a solvent, it can be granulated by a suspension polymerization method, and other methods such as a spray drying method can be used.

Coating methods include forming a layer containing a CG material on top of the core material to form a multilayered polymer by emulsion polymerization or suspension polymerization, or spraying it onto the core material. A method of coating a layer containing a CG substance using a dry method can be used.

The thickness of the coating layer is in the range of 0.1 to 10 μm, preferably 0.1 to 2 μm, and depending on the type and bond of each composition, in practice, the thickness of the coating layer may vary depending on the type and bond of each composition. Appropriate conditions are selected depending on the characteristics such as print density when forming an image.

Since the transparent toner produced in two series is obtained in a spherical shape, it has good fluidity and stable magnetic chargeability.

By forming the coating layer to be as thin as described above, light can easily pass through it. Therefore, no matter how many six layers of toner deposits are formed, light cannot reach the lower layers, and it can be expected that charge generation will be performed efficiently.

The photoconductive toner of the present invention can be used in a copying machine that does not have a photoreceptor. Therefore, the simplification of copying machines,
Be able to reduce manufacturing costs. Further, the electroconductive toner of the present invention can be used in a conventional single copy machine.

Furthermore, as the photoconductive toner used in the present invention, by selecting toners of colors corresponding to each of the three primary colors and using them in combination, there is a possibility that it can be used in a full-color process in one yacht. Hara chiron desu.

The present invention will be explained below using examples. In the examples, "parts" represent "parts by weight."

Judake carp L (a) Production of core particles Styrene 70 parts n-butyl methacrylate 30 parts 2-2'-azobisisobutyronitrile 2 parts (polymerization initiator) Add 100 parts of ethyl acetate to a homogeneous dispersion having the above composition. Diphenylhydrazone (chemical formula A) was added and homomixing was performed at room temperature for 10 minutes at 00 rpm.

This mixture was degassed and replaced with nitrogen, then heated to 70°C and polymerized for 6 hours while stirring normally.

The above mixture is added dropwise to an lvt% polyhinyl alcohol aqueous solution while stirring at 400 rpm using a TK homomixer.

Thereafter, the temperature was raised to 70° C., and the mixture was stirred at 400 Qrpm for 3 hours to perform granulation while removing most of the ethyl acetate.

Next, pour this solution into 2e of methyl alcohol, use a centrifuge to separate the particles and the solution, decant the solution, add a new water-methyl alcohol solution of 1 L and 2σ, and repeat the same operation 3 times. The reaction product was repeatedly dried to obtain microparticles with an average particle size of 2 μm.

(b) Production of photoconductive toner (coating of layer containing CG substance) CG substance: Chlorodiampurus - 50 parts (chemical formula (B)
) 40 parts Thermoplastic resin: Styrene 70 parts n-butyl methacrylate 20 parts diethylaminomethacrylate 10 parts Copolymer ('I''g=63°C
, i'm=l32°C1Mw/Mn=I 5)
I After uniformly dispersing and stirring 0 parts or more of the substance in toluene by high shear stirring, this Example (
As a result of adding the core substance prepared in step a) and spray-drying the surface coating using the spray try method, the average particle size was 12.
µm surface coating layer 0.8 µm photoconductive toner obtained from said leading? A-type toner is uniformly spread on a brass substrate, corona charging is performed on it at ±5 KV in a dark place, followed by exposure to form an electrostatic latent image, and then plain paper is closely attached on top of it. From the paper side, apply a voltage of 15KV, which is the opposite polarity to the above-mentioned charging polarity.
The toner in the latent image area is transferred onto plain paper by corona charging. This heat fixing was performed to obtain a clear blue-purple positive image.

Example 2 (a) Production of nuclear particles As the CT material, 2-ethyl-4-nohenynaminobenzaldehyde diphenylhydrazone (formula (D) below) was used instead of p-noedylaminohenzaldehyde diphenylhydrazone.
It was produced in the same manner as in Example 1 using.

As a result, microparticles with an average particle size of 12μ were obtained.

(b) Production of photoconductive toner (coating containing CG substance) CG substance (ε-type copper phthalonoanine) 25 parts CG substance (use the same one used for the core particles) 50 parts thermoplastic resin ( 25 parts of a photoconductive toner prepared in the same manner as in the other examples and having an average particle size of 14 μfl+ and a surface coach ink layer of I μm was used.

When an image was formed using the toner in the same manner as in Example 1, a clear blue image was formed on plain paper.

In accordance with the present invention, a cutting die of the invention comprises a core material impregnated with a charge transporting material and a coating layer provided on the surface of the core material and containing a biomaterial developed by the community. By using the U-type toner, light generation::: , +, clearing efficiency is achieved,
It can travel the shortest distance, and has high transparency in both the upper and lower directions.
An improvement in photosensitivity can be achieved.

[Brief explanation of drawings]

FIG. 1 shows a schematic structural diagram of the toner of the present invention. FIG. 2 shows a conceptual diagram of carrier movement in the toner of the present invention. FIG. 3 shows a conceptual diagram of carrier movement in a conventional toner. The symbols in the figure are as follows. !・・Nuclear body core material, 2・・Coating layer, 3・
...Light, 4..Substrate, 5..Direction of f-hyperactivity of carrier, 6..Toner particles. Figure 1 Figure 2 Figure 3 Agony

Claims (1)

[Claims] 1. (a) Nuclear body core material containing charge transport material and (
(b) A photoconductive toner comprising a coating layer containing a charge generating substance provided on the surface of the nuclear core substance.